1. Field of the Invention
The present invention relates to a magnetic tape cartridge, and more specifically, to a magnetic tape cartridge which a detector can surely detect.
2. Description of the Related Art
In companies, organizations, institutions, and so on which handle a large amount of data or very important data such as personal information which require security protection, the data are saved in a large capacity of recording medium so as to be backed up. Thus, it is possible to prevent loss of the data. A magnetic tape cartridge is used as the recording medium to back up the data due to its large storage capacity, reliability, and easy handling. Moreover, the magnetic tape cartridges which hold the back-up data are collectively stored under strict management in a controlled area such as a storage house or a storage room where human access is controlled. Thus, it is possible to restrict and control the magnetic tape cartridges being carried out so as to prevent loss of the important data. For instance, a cartridge storage rack 61 shown in FIG. 6 is placed in the controlled area where ID authentication with an ID card or the like is required to restrict people to enter freely. In addition, the magnetic tape cartridges MCs which hold the back-up data are stored in the cartridge storage rack 61. In this case, a label which shows a management number for identification, description of the saved back-up data, a back-up date, and so on is affixed on each of the magnetic tape cartridges MCs. Then, each of the magnetic tape cartridges MCs is stored in the cartridge storage rack 61 with a labeling side 62 facing outside so that the items shown on the label can be seen.
However, even in the controlled area where human access is controlled, it is necessary to monitor each of the magnetic tape cartridges MCs itself. By so doing, it is possible to restrict each of the magnetic tape cartridges MCs being carried out of the controlled area. Otherwise, a person who enters into the controlled area can easily carry out the magnetic tape cartridge MC from the controlled area.
In view of the above, to prevent the magnetic tape cartridge MC from being carried out of the controlled area, a security tag is affixed or attached on each of the magnetic tape cartridges MCs. This makes it possible to monitor the magnetic tape cartridges MCs not to be carried out of the controlled area freely. However, the security tag is conventionally put on an outside of the magnetic tape cartridge. Therefore, when the security tag is detached, a detector cannot detect the magnetic tape cartridge even though the detector is set in a doorway. As a result, it is possible to carry out the magnetic tape cartridge from the controlled area.
For this reason, a magnetic tape cartridge with a built-in security tag which is not easily detached is proposed (See JP 2004-127349A). However, the conventionally proposed security tags in the magnetic tape cartridges are described merely about how to install the security tags in the magnetic tape cartridges with consideration of shapes and so on of the magnetic tape cartridges. Therefore, the security tags are described without consideration of detection of the security tags, which is to be a principal object.
By the way, as shown in FIG. 7, when a large number of the magnetic tape cartridges are carried out of the controlled area, the magnetic tape cartridges MCs are loaded onto a carrier cart 71 and then carried out. Moreover, as shown in FIG. 5B, the magnetic tape cartridge MC may pass through a service window and then be carried out of the controlled area.
When the carrier cart where the large number of the magnetic tape cartridges are loaded, or the magnetic tape cartridge passes by a detector (through a security gate) placed in a doorway of the controlled area, it is detected whether the magnetic tape cartridge has the security tag or not. At this time, each of the magnetic tape cartridges is usually loaded onto the carrier cart with the labeling side facing outside so that the magnetic tape cartridge can be visually checked. And, the labeling side of the magnetic tape cartridge usually faces outside also when the magnetic tape cartridge passes through the service window. In addition, when the magnetic tape cartridge is stored or carried, the upper surface of the upper half of the magnetic tape cartridge faces a ceiling. Otherwise, when the magnetic tape cartridge erects, the labeling side is designed to face upward (in a case of one reel) or sideways (in such a way that a supply reel is placed lower than the other reel in a case of two reels). Therefore, the magnetic tape cartridges are not to be carried with the upper surfaces of the upper halves facing a floor even using methods other than the carrier cart.
However, in the magnetic tape cartridge described in JP 2004-127349A, it is merely described that the security tag is arranged at an opposite corner from a position where a write protect tag or a built-in tag to identify a type of the magnetic tape cartridge is placed, or the like. Therefore, no situation of the security gate or carrying out of the magnetic tape cartridges is considered. As a result, the detector may be impossible to detect the security tag since a detection signal from the detector or the like may be blocked depending on methods or ways to carry out the magnetic tape cartridge.